Currently it's my LCD-XC, but I haven't tried a lot of headphones. My other reference points for closed backs are N90Q, JM modded HE R9 and ATH-W5000. It brings out details and texture best though isn't the most natural sounding.

I also found the spark to sound warm but I can't stand it in high gain. Staging is way off to the point of being obnoxious. In low gain it sounds fine though. I would say it's all just placebo but I can say with confidence the treble is noticeably less fatiguing than what I'm used to. So much so I can listen to my edition 10 at mid/high volume without EQ on it and it's bearable, something that's impossible to do on my other amps.

So I have a theory that we could take tools commonly used in an audio mixing environment to gain more knowledge about how different headphones sound, but I don't have the gear to try and validate that. I have however done some listening in my DAW using various softwares and I think there's untapped potential there.

As an example it's common in mixing to have a mid/side EQ to independently adjust centered (mono) and side (stereo only) information. I tried simulating a typical sine wave sweep but for the mid and side signals separate and found both signals to have different peaks/dips from each other. My LCD-XC has a boost at 7-8k that is only present on the side signal whereas that region is slightly attenuated on the centered signal (for my hrtf anyway). Obviously I would need to do more thorough testing with actual measurement equipment to validate that, but it's an interesting observation nonetheless.

Fr though do you actually have the $9k Audio Technicas?

Based on the marketing it seems to have motors inside similar to Skullcandy crushers to provide some sort of haptics for AR applications. Not the worst idea I've seen but it looks like a $10 headphone.

If I didn't already have headphones like this (LCD-XC) I would jump on this.

I've had a good experience using apple music on Android. Technically you can get better sound quality out of tidal because UAAP supports tidal streaming (UAAP bypasses android's audio processing) but it takes a decent amount of listening training and a transparent setup to even hear that difference so I wouldn't worry about it. Imo apple music is a good middle ground offering good enough sound quality while still being reasonably convenient.

I've heard headphones that sound close to nearfield monitors (akg N90Q) but not a full room setup.

I find this happens when you get a headphone with good enough acoustics that once you EQ it to your ears it disappears. The JM modded HE R9 does that for me.

There's an obscure album that I have downloaded years ago that for some reason isn't available online anymore. Good thing I have it on multiple devices.

The sacred wave.

Chances are you won't hear a difference. A dac/amp isn't worth getting for most people.

Woods of mystery - Theophany

This track is very immersive and has a lot of different sounds. Imo it can test most aspects of a headphone.

1. Immersive staging with sounds moving around the mix.

2. Different bass sounds like low tumbling rumbles to bell like low percussion.

3. Sound FX like chirping animals, fast breathing and walking.

As someone that leans more towards the subjective persuasion the differences between sources are minimal if you compare two reasonably competent ones. Even then the potential improvements are dependent on how you listen and what you listen to. If you can't hear a difference don't be persuaded to buy more expensive gear and enjoy what you have.

I typically use EQ on most of my headphones to get the tonality I want but there are some oddities I've experienced when doing so that aren't exactly technical performance changes though they do have an impact on enjoyment. Auto EQ is my go to but Harman target doesn't sound good on some headphones. I can't stand it on my LCD-XC but it sounds great on my Ora graphene Q, both of which measure very close to Harman once auto EQ is applied. Another issue I've had is some amps distort the bass when I use a bass shelf but some don't.

Imagine having a headphone so neutral it has no bass, mids, or highs.

I used to do this with my HE400i. It actually makes a decent speaker though it's not very loud.